You folks just dont get the implications of this do you?.
When (notice i said 'when' and not 'if') Yellowstone blows its top, you can kiss everything you know now as 'normal' goodbye, no electricity (yup, no PC's either) no fuel, no food, no water, no AC, no gas..nothing...and dont expect FEMA to come running to help, cos they are gonna be too busy trying to survive themselves!.
You CANNOT expect any government to help in such an event, and to suggest that you could build bunkers and store enough food is absolutley rediculous!... you are a country of over 200 million people, if 10% (i guess it would be a LOT more than that) were affected by an 'event' such as Yellowstone, thats 20 million people!. Where do you suggest you store all that food, water?..not to mention toilet facilities!!.
When it does go (or we get struck by a comet) then its every man, woman and child for themselves... Sorry to be so blunt, but thats the reality!.
Perhaps when you are sitting there in the dark, choking to death, with ash falling all around you, you might remember exactly how childish some of the comments on this thread have been.
Yeah, i am in the UK..but am soon to move to the US!...